#include <iostream>
#include <vector>

class A {
public:
    A() = default;

    A(const A& o)
    {
        std::cout << "A(const A& o)" << std::endl;
    }

    A(A&& o) noexcept
    {
        std::cout << "A(A&& o)" << std::endl;
    }
};

int main() {
    std::vector<A> va;
    va.reserve(2);

    va.push_back(A());
    va.push_back(A());
    va.push_back(A());


    return 0;
}